The requirement to remember the churban is incumbent upon Jews every day (top of page 2) and is especially important at times of joy. Aside from the practices of leaving a wall unfinished/unpainted, ...
From what I understand, we outside of Eretz Yisrael we keep two days of Yom Tov as a continuation of the minhag that evolved from the time of the Bais Hamikdash when we would not necessarily know when ...
[Edit: According to Nusach Edot HamMizrach,] why does the Mussaf prayer on Shabbat and Rosh Chodesh include a description of the actual mussaf sacrifice, while the Mussaf prayer on Moed does not? Why ...